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Old Servel gas A/C

My aunt, who bought her house in 1977, is finally thinking about replacing her furnace and A/C this spring.

I got to thinking about this system after she was talking to me about it, because I had not even been in her house since I was 8 years old, but I remember the system rather well.

The furnace was this dark grey gas unit, and I think he name was Brentwood....It is the only furnace I have ever seen with that name on it. I think the name was actually on a label with some kind of logo that was a light blue oval with the name inside of it.

What I always remember more than anything was the A/C. I was always curious how the system worked, but I never have gotten to work on one, and I don't even really see any units like this around anymore.

The condenser was a big blue thing that was made by Servel.

Here are a few things that I always had questions on, but never really knew anyone that could anser them.

1 She had to have a company come out every spring to service it and start it - she said that the original company told her that during the winter when it was not being used, it shut itself off inside and needed to be restarted in the summer. Ever hear of such a thing?

2. The WEIRD sequence of operation. When the thermostat called for cool, the indoor blower started, but the condenser did not start for about 3 minutes after the call for cool. I figure maybe this was a delay on make control, but here is where it gets strange:

When the thermostat satisfied, the indoor blower stopped right away, but the outdoor condenser unit continued to run for about 3 minutes after the thermostat satisfied. I never did understand why.

3. The unit never cycled from the time it was new. She said she had to keep the thermostat at 68 because the house just would not stay cool if she had it any higher. If she let it run 24/7 the unit would keep running until 2 in the morning when the house finally got down to temp, but once it started back up, around 7 or 8 in the morning, it would just keep running all day and into the night.

She said it ran that way from the day it was installed. So, could this mean that the unit was never charged properly from the start? Or is gas A/C just not as fast to cool as electric A/C?

I would love to hear from guys who worked on these - did you like them, were they hard to work on, were they good units, ETC.

I have a friend in Harrisburg who has one. I did some searching around to find a guy that used to work for UGI who knows absorber chillers. He comes out and does the startup and shutdown for her, and he is very reasonable. If it doesn't have a compressor, I'm lost!

Thew unit works great. She checks the water once in a while, and she's good to go!

Pulled one out when I first got in the trade, very unusual unit. We had been warned about the ammonia being 'bad' stuff, certainly worth remembering if you end up working on it or removing it. The condenser was so big and so heavy, we hired a crane to lift it out of the backyard. He couldn't get his outriggers all the way out, started to tip once the weight was fully on the boom. Then he made a mistake, backspooled the cable and hit the brake just before it came back to ground. Bent the boom, made for a very unhappy crane operator. Might be easier to turn it into a garden shed than remove it.

Gas companies pushed them really hard in the 60's and 70's. They are absorbsion chillers and not a typical condensing unit. When the TStat called for cooling the Servel took a while to produce chilled water so hence the delays.

The thermostat actually lit up a burner(s) inside the Servel, which heated up the chemicals inside the sealed chamber that caused the cooling effect. Once cooling started there was also a small chilled water pump that pumped the chilled water to the inside cooling coil. So the lines run into the home should be water lines and not refrigerant lines.

Two big problems. Sometimes while operating or sitting over the winter the salt brine and the other chemicals would separate and a technician had to go through a process to get the thing to cool again.

Second problem is the design temp of the chilled water was not as good as a DX system in removing humidity. And most of those systems, including the large commercial ones, were sold and installed on the East Coast where humidity is a big part of the comfort picture.

The complications and the initial install costs pretty well did them in.

If you find any technical info, pictures or sales brochures a few of us on this board sure would like to see them.

"The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
- Alexis﻿ de Toqueville, 1835

I used to work on them under a guy named Brian West way back when. Had me do everything accept the ammonia side. A big problem with them is people dumped automotive antifreeze in them, since they were open to the air it would foul, and coat everything with a slime. Brian West had a solution he made up himself, it's been too long to remember what it was. I do remember mixing Methyl alcohol with it, because it was so dangerous. A properly tuned system would actually out cool and dehumidify better than a Compressor system due to the coolant tank and lower than refrigerant temperatures, and the fact the whole coil was at a colder more even temperature.

worked on many!

I def. remember the slime! wash out the chiller barrel n drip tray, might've been the original double row condenser coils, and you had to wash between them, but ya couldn't split em, but there was a bout a 1/4" spacing so it could be done. Remeber venting off the noncondensables into a bucket of water oh so slightly!!! didn't want that hose whipping round! generator would get sooted up because the burners would get fouled, that had to have been asbestos in there! well, at least it was wet then. Once ya knew them, they were pretty easy.

ct_hvac_tech, Does your Aunt live up north? I have relatives that live in upstate New York, they cool their houses with city water, the water is pulled off the main thru the regular house meter, thru the cooling coil, especially made for potable water. Then thru a small bronze pump, another meter and back into the main downsteam. The water authority is happy to have them temper the water, of course they don't need much cooling.

ct_hvac_tech, Does your Aunt live up north? I have relatives that live in upstate New York, they cool their houses with city water, the water is pulled off the main thru the regular house meter, thru the cooling coil, especially made for potable water. Then thru a small bronze pump, another meter and back into the main downsteam. The water authority is happy to have them temper the water, of course they don't need much cooling.